Chapter 5 : Response in Plant

Question 1

Types of response :

Answer 1

Tropism and nastic response

Question 2

What is tropism?

Answer 2

Tropism is a type of growth response of parts of plants such as shoots or roots that grow towards or away from stimulus .

Question 3

Characteristics of the response :

Answer 3

One directional , Irreversible , slow and not apparent

Question 4

Types of tropism :

Answer 4

Thigmotropism , phototropism , hydrotropism , geotropism , chemotropism

Question 5

What is thigmotropism :

Answer 5

Plant response to touch

Question 6

What is chemotropism :

Answer 6

Plant response to chemical substances

Question 7

Meaning of nastic response :

Answer 7

Plant movement that occurs in any part of the plant in response to external stimulli

Question 8

Characteristic of nastic response :

Answer 8

Non-directional , reversible , fast ,apparent

Question 9

Photonasty :
Example

Answer 9

Non-directional movement of plant response to light . Flower petals open during the day and close during the night .
Example : dandelion , morning glory

Question 10

Seismonasty :

Answer 10

Caused by mechanical shock . Parts of the plant that show this response are stigmas , stamens and leaves.
Example : Neptunia

Question 11

Thermonasty :

Answer 11

Response due to change in temperature. Flower open when temperature rises and close when temperature drops.
Example : tulip

Question 12

Nyctinasty : 感夜性

Answer 12

Response due to the variation in light and temperature .
Related to day and night also known as sleeping movement .
Seen in leguminous plants.
Leaves of leguminous plant fold at night and opens during the day.
Example : long bean

Question 13

Thigmonasty :

Answer 13

Due to vibration .
Some parts of the carnivorous plant will bend over when come in contact with insects .
Example : venus flytrap , pitcher plant

Question 14

Similarities of both response :

Answer 14

Both happens in plants .
Both respond towards a stimuli

Question 15

Differences of both response : Direction Respond

Answer 15

Tropism : Respond to directional stimuli
Nastic response : Respond to non-directional stimuli

Question 16

Differences of both response : Direction response

Answer 16

Tropism : Depends on the direction of stimulus
Nastic response : Does not depend on the direction of the stimulus.

Question 17

Differences of both response : reverse

Answer 17

Tropism : Response is irrreversible
Nastic response : Response is reversible

Question 18

DIfferenes of both response : growth

Answer 18

Tropism : It is a growth response
Nastic : not

Question 19

Differences : speed , apparent

Answer 19

Tropism : slow and not apparent
Nastic : fast and apparent

Question 20

Differences : occur

Answer 20

Tropism : Occur at shoots and roots
Nastic : Occur at any part of the plant

Question 21

Differences : example

Answer 21

Tropism : light , gravity , water , touch and chemical substances
Nastic : light , temperature , contact , heat and vibration

Question 22

What are phytohormones ?

Answer 22

Phytohormones are plant hormones that stimulate and coordinate response in plants.

Question 23

Example of phytohormones that simulates growth

Answer 23

Auxin, gibberellin , cytokinin

Question 24

Example of plant hormones that inhibits growth

Answer 24

Abscisic acid , ethylene

Question 25

Function of auxin : shoot tip and root tip

Answer 25

Stimulate cell elongation at the shoot tip and root tip . Causes growth in the root and shoot of plant.

Question 26

Function of auxin : adventitous roots

Answer 26

Stimulates growth of adventitous roots . Promotes growth of adventitous roots in stem cuttings .

Question 27

Function of auxin : seed
what is the process called ?

Answer 27

Stimulate ovaries in flowers to form seedless fruits
-auxin is sprayed on stigma or ovary of flowers to stimulate the ovary to develop into fruit without fertilisation
-this process is called Parthenocarpy
- ovule of the flower will not develop into seedf

Question 28

Function of auxin : inhibits weeds

Answer 28

Inhibits the growth of weeds in high concentration
-auxin in high concentration is used as herbicide

Question 29

Function of auxin : Prevent fruit / leaves

Answer 29

Prevents fruits and leaves from failing off prematurely
-Prevents fruits and leaves that are not fully developed yet from falling off

Question 30

Function of auxin : Inhibits growth of lateral buds into shoots

Answer 30

Promote growth at the apex of the shoots
-prevents shoots from branching out of the plant , making them grow taller and straight

Question 31

Function of gibberellin : cell elongation

Answer 31

Stimulates cell elongation in shoot
-promotes the growth of stem and shoots
-stimulates elongation of cells in fruits ,making them grow bigger

Question 32

Function of gibberellin :enzyme

Answer 32

Stimulates enzyme production in germination of seeds
-Speeds up germination of seeds

Question 33

Function of cytokinin 细胞分裂 : cell division

Answer 33

Stimulates cell division and cell elongation in the presence of auxin
-Promote cell division and growth in tissue culture to produce new plants called clones

Question 34

Function of cytokinin : delay aging

Answer 34

Delay aging and death of leaves
-keep plants fresh and green

Question 35

Abscisic acid 休眠素 :

Answer 35

Inhibits growth of shoots and promote dormancy (deep sleep) in seeds
-prevent seeds from germinating and shoots from branching out

Question 36

Ethylene (in the form of gas) : harvest / ripe

Answer 36

Stimulates ripening of fruits
-causes fruits to ripe naturally
Stimulates fruits and leaves to fall off
-fall during harvest time

Question 37

Where is auxin produced :

Answer 37

Auxin is produced at the apical meristem of shoots and roots in the zone of cell division

Question 38

How does growth response occur ?

Answer 38

Auxin diffuses into the zone of cell elongation to promote growth .

Question 39

When is the distribution of auxin uniform ?

Answer 39

When there is uniform light or in the dark
Shoot/root grows straight up